Figure 5. Representative current traces from cells co-expressing Kir6.2ΔN2−30, Kir6.2K185Q or Kir6.2ΔN2−30/K185Q mutant subunits and SUR1.

Currents recorded from inside-out membrane patches containing wild-type or mutant K_ATP channels at -50 mV in K_int solution (see Methods). Patches were exposed to differing [ATP] as shown. For the ATP-insensitive dual mutant channel Kir6.2ΔN2−30/K185Q + SUR1 the baseline current was determined by subsequent irreversible inhibition of channel activity with 10 mM MgCl₂ and 2 mM CaCl₂ (see Methods).